The present invention relates, generally, to an apparatus and a method for allowing communication systems to coexist and, more particularly, to an apparatus and a method for allowing multicarrier systems to coexist when there is a jointly used transmission medium.
As a result of a significant escalation in radio communication systems, in particular, the case will frequently arise in the future that two or more independent communication systems use the same transmission medium, such as frequency bands. This can result in interference until one or more of these communication systems fails.
When using, by way of example, two communication systems which operate on the basis of the same transmission method or transmission format (e.g., DECT), the standards stipulate methods for avoiding such interference. These conventional methods are known, by way of example, by the term dynamic channel allocation. A drawback of such conventional methods, however, is the fact that independent communication systems operating on the basis of the same transmission method or on the basis of different transmission methods do not communicate about the use of the jointly used transmission media.
Particularly when using independent communication systems operating on the basis of different transmission methods, such as DECT and PHS systems, interference which is sometimes considerable arises which can even result in one type of communication system failing. A field trial testing DECT systems against PHS systems, where more and more DECT and PHS systems were turned on in succession, saw, by way of example, the PHS systems fail after the DECT systems interfered with the PHS systems' control channels, firmly allocated on particular frequencies, due to a lack of free carrier frequencies or time slots.
The present invention is, therefore, directed toward an apparatus and a method for allowing communication systems to coexist which is simple and inexpensive to implement.